Liquid-metal valve



Sept 15, 1964 E. B. sEvETz LQUIn-METAL VALVE 3 Sheets-Sheet 1 Filed Feb.14, 1962 r NN u II W 4 l r l: f NS .I Tf r, NN Vl .I .C2 xvi Ww alli'MN\ (N N lwim.. m wk z T e Y www il ma .m VD ma .A A WW w Y B Sept. 15,1964 E. B. sEvETz 3,148,859

LIQUID-METAL VALVE Filed Feb. 14, 1962 3 Sheets-Sheet 2 \& A

SEVETZ BY /y Wad/LJ NVENTGR EDWARD B- wN NN MN NmUTm ATTORNEY 3Sheets-Sheet 3 E. B. SEVETZ LIQUID-METAL VALVE Sept. 15, 1964 Filed Feb.14, 1962 l INVENTOR EDWARD B. SEVETZ BY f??? 3C/Mw ATTORNEY UnitedStates Patent() M 3,148,859 LIQUID-METAL VALVE Edward B. Sevetz, WestHartford, Qonn., assigner to United Aircraft Corporation, East Hartford,Conn., a corporation of Delaware Filed Feb. 14, 1962, Ser. No. 173,227 2Claims. (Cl. 251-62) This invention relates to high-temperatureliquid-metal valves. In valves of this type the valve body and the valveseat are subject to distortion from their true shape due to thermalexpansion and heavy pipe loads producing misalignment of the valve stemassembly and distortion of the valve seat. As a result, in order to seatthe movable valve plug into the stationary valve seat, a very largepiston force upon the valve stem is required to overcome thismisalignment. This in turn results in bending the valve stem and gallingthe valve stern bearings, permitting the valve to leak.

It is an object of this invention to provide a hightemperatureliquid-metal valve which is free from these diiculties.

To prevent leakage past the valve stem, it has been common practice toprovide a bellows seal. The bellows soon fails due to the hightemperature and because it is located in the liquidmetal flow area, auttering vibration is frequently set up which flexes the bellowsresulting in an early failure.

It is a further object f this invention to provide a liquid-metal valvein which the stern Iassembly is sealed by a bellows and in which meansis provided to protect the bellows from the high-temperature liquidmetal and, otherwise, to prevent bellows failure.

A further object oi this invention is to prevent distortion of theannular stationary valve seat, permitting the latter to conform to thevalve plug seating geometry With very light valve stern loading.

A still further object is to provide improved valve stem guide bearingswhich have normal close tits with the valve stem, except very liberalbearing tits are encountered in the nal axial travel of the valve sternassembly just before the valve plug contacts the valve seat.

A further object of the invention is to provide means for reducing thedow of heat from the liquid metal in the valve body into thevalve-actuating and sealing area.

A further object or" the invention is generally to improve theconstruction and operation of high-temperature liquidmetal valves.

These and other objects and advantages of the invention will be obviousor will be pointed out in connection with the following detaileddescription of a preferred embodiment of the invention shown in theaccompanying drawings. In these drawings:

FIG. 1 is a side elevation of the liquid-metal valve of this invention;

FIGS. 2 and 2a are sectional elevations, in perspective, of dividedparts of this valve, with the dividing line being indicated by Z-Za inFIG. l;

FIG. 3 is a detail view showing a modified construction of the valve inthe vicinity of the movable and stationary valve members, the valvebeing shown in the closed position; and

FIG. 4 is a similar view showing the modified valve in its openposition` As shown herein, the liquidmnetal valve of this inven-3,148,859 Patented Sept. 1 5., 1 964 ICC tion is adapted for horizontalmounting, although it may be installed in a vertical position with thevalve stem up. The valve consists of a valve body 10 having an inletport 12. and an outlet port 1d. The valve body denes a valve chamber 16in which the annular stationary valve member 1% and the movable plugmember Ztl are located.

The valve body carries an outer elongated tubular casing 22 whichsupports at its free end a cylinder 24 for a valve-operating piston Z6.The movable valve member, or plug, Ztl is mounted at one end of areciprocable valve stem assembly 23 which is operatively connected tosaid valve plug 2@ at said one end and to said piston at its other end.An intermediate tubular sleeve 3i), which is spaced from the valve sternassembly and from the .outer casing 2.2, is connected to said valve body1li at one end and to cylinder 2d at its other end, and is provided withan annular thickened extension 31 at its left-hand end (FIG. 2) whichprojects into the valve chamber 16. The valve back seat 124 on abutment64 engages the movable valve stem member 117 and limits the valve in itsopening movement. Extension 31 carries a journal 32. in which a bearing31tof the valve stem assembly is slidable, bearing 34 being threaded atits forward end at 36 into an internal recess in plug 20. The forwardend of bearing 3d engages a flange 38 of a tube 4t?, the forward end ofwhich engages an abutment l2 on the plug Ztl. Tube di), Where it isattached to the plug, is of substantial Wall thickness, but outside thevalve body it tapers to a very thin-walled section 4A- Which extendsoutwardly of the valve body within casing Btl to a point midway ofhousing 22. At this point tube t4 is closed by a solid closure member4d. One end of a sealing bellows 48 is secured in a duid-tight manner tothe front end of stem 52. The other end of bellows 48 is secured in -afluid-tight manner to a shell 50 which is likewise mounted in afluid-tight manner by a weld 7 8 on the inner end of tubular member 3@and by a weld dil on outer casing member 22. Members 22 and Sil andshell Sil are secured at this point to the front portion of cylinder 2d.The valve-operating stem 52 is screw-threaded at the front end onto astem 54 of member 46 and extends rearwardly through a journal .'37carried by shell 5@ and at its rear end stern 52 is screw-threaded ontoa stem 117 of a threaded portion 118.

tern 117 extends rearwardly through a second sealing bellows 5S andterminates at its free end in a threaded portion 6d which is threadedinto piston 26. Bearing 56 has four axial flutes which engage journalS7. A spring 62 bears against piston Z6 and against an annular abutment106 carried by cylinder 24. One end of bellows 58 is secured to abutment64, its other end being connected to an outstanding ilange 66 on thestern 117.

When the valve is open, liquid metal in chamber 16 communicates throughholes 68 with the space 119 between the thin-walled tube 44 `andintermediate tube 30 and surrounds bellows d8 and iills chamber 7 tibetween the bellows and ilange 121D. When the valve is closed, thisliquid metal drains from chamber 70 into outlet port 14. A high-pressuregas introduced at port is provided in chamber 72, which also occupiesthe interior of bellows 48 for the purpose of balancing the pressure'ofthe liquid metal surrounding the bellows. A low-pressure gas is alsoprovided in the space 121 between casing 22 and tube 30. This gas alsofills the spaces between heat battles 74 which surround the valve bodyand control the escape of heat from the valve body. The inert gasbetween the adsense Si baihes is contained by jackets 76 and preventscorrosion of the valve body at high temperatures. The jackets areseal-welded at joints 73, Si), S2, Sd andil. It will be understood thatthese jackets extend about inlet l2 and outlet ld and are seal-weldedthereto, these parts having been broken away in the drawing.

Referring more in detail to certain of these assemblies, it will benoted that the stationary annular valve seat i8 is a tubular memberhaving an annular spherical-surface Seat 88 at its rig t-hand end andhaving an outstanding annular flange 9d at its other end which engagesilange abutments on valve body lil; t will also be noted tha the sleevellt', is spaced from the valve body about its entire periphery baclr toa tiange 92 on the valve body, providing ample clearance 9dabout memberi8 to .vhicA the liquid metal in the valve body has access. As a result,the problem of valve-body distortion at high temperatures is eliminated.

In order to insure that the valve plug 2li is accurately aligned withthe annular spherical-surfaced seat SS when the valve is closed, thesliding bearing 34 is provided with a reduced portion which moves overthe left-hand end of journal E?, in the linal closing movement of thevalve. Accor ingly, the valve stem assembly has a normal sliding lit inits guide bearings during valve movement, except when in the axialtravel of the valve stem assembly, just before the valve plug contactsthe valve seat, the clearance between the bearing 3d and the journal 32is increased, permitting the valve plug to locate itself 1n the valveseat without mterference and without galling of the guide bearings.

In order to minimize the heat transfer from the liquid metal in thevalve body l@ in the direction of the sealing and operating mechanism ofthe valve, the tube 23, which is preferably made of columbium, is madewith a very thin wall and the cavity 93 within this tube is iilled withtantalum Wool which has a very low ieat conductivity. This chamber isalso filled with an inert gas which is low in heat conductivity and isthen sealed leali-tight by welding nipple 122. The metal wool preventstransfer of heat axially along the shaft by convection of the gas.

The valve is pneumatically operated through piston 26 and, therefore, issuited for remote control operation. Gas is introduced at 123, whichacts on one side of the piston to open the valve, and at tdi/l; to acton the opposite side of the piston to close the valve. Compressionspring 62, which has one end seated on the left-hand face of the piston26 (FIG. 2A) and its other end bearing against an internal flange M96 oncylinder 24, thus serves to return the valve to open position in theevent that pressure of the valve-actuating gas fails. Liquid metal inchamber 1219 is prevented from entering chamber 72; by welds 73 and 8l).Liquid metal is prevented from entering chamber 72 along the shaft bybellows 48. In the event of liquid metal reaching chamber '72., it isprevented from entering the actuating gas chamber by bellows andbackstop seat 124.

The axial shaft, or stem 52, is supported by the two axially spacedbearings 34 and 56, each of which has axial flutes to reduce the bearingarea, since surfaces of this sort are susceptible to self-welding at thehigh ternperatures prevailing in liquid-metal valves. It will be notedthat the bearing at 3d runs in liquid metal, whereas the bearing at 56runs in a gas atmosphere.

All the parts of the valve which are exposed to liquid metal are ofcolumbium or other material compatible with the liquid metal used,except for the stationary valve seat 1S, plug member 2), and bearing andjournal members 34, 32, which are made of suitable bearing materials.

In FIGS. 3 and 4 I have shown a modified form of liquid-metal valvewhich has stationary and movable valve members which have a permanentseal formed integral therewith, thus insuring zero leakage until theseal is intentionally ruptured by the initial opening of the valve.Thereafter, the valve ,controls the llow of liquid metal by thecooperation of its stationary and movable valve members in the mannerdescribed above in FIG. 1.

In these figures, the valve body lila encloses a chamber ida in which astationary valve member 1&1 is mounted. A movable plug 29a cooperateswith the annular spherical-surfaced valve seat d8a, as described inconnection with FIG. 2, being axially movable by a valve stem Zia. lnthis modilied form, plug 2da is made with an axialthreaded hole in whicha thimble il@ is screw-threaded. Thimble llt) has a hanged annular rimterminating in a cutting edge M2 located in spaced relation in front ofthe plug member 2li-rt. An inlet pipe 113 is provided, which is weldedat lid to valve body iba and has its end terminated adjacent cuttingedge lll. Pipe 113 and plug 26a are connected by a transverse web 116which lies in position to be engaged and severed by the annular cuttingedge lli if the valve stem Zia is moved axially to the right in FIG. 3in a valve-opening direction. The web lle is shown herein as an integralpart of plug 20a and pipe 113 which provides a sure seal againstliquid-metal leakage.

In PIG. 4, the parts are shown in the position they occupy after thevalve has been opened. It will be noted that the web lie has beencompletely severed, but still remains attached to plug Zilla, so thereis no chance of its getting loose in the system. Also, it will be notedthat the pipe M3 is freely open for liquid-metal tlow and that thethim'ole and web do not prevent subsequent opening and closing of thevalve.

lt will be evident that as a result of this invention a particularlyeffective liquid-metal valve has been provided wliich is resistant tothe corrosive action of liquid metals and effectively seals such metalsagainst leaking.

It will also be evident that means has been provided in this valve toinsure seatin:y of the movable valve member without excessive forcebeing required on the valveoperating stem. Also, provision has been madeto provide a completely leali-proof valve during the period from thetime the system is initially put in service until such time as the valveis intentionally opened and thereafter to provide for the control of theliquid-metal dow by virtue of improved cooperating stationary andmovable contact members.

Two embodiments of the invention have been illustrated and described,but it will be evident that many variations may be made in theconstruction and arrangement of the parts within the scope of theappended claims.

l claim:

1. In a high-temperature liquid-metal valve, a valve body having inletand outlet ports, a valve casing comprising an elongated tubular membersecured at one of its ends to said valve body, an annular valve memberxed to said body about one of said ports, a cooperating movable plugmember, a valve stem on one end of which said plug member is carried,said stem having two axially spaced guide bearings reciprocable injournals in said casing, one of which is located near said end whichcarries said plug member, said stem bearings having a normal closesliding t in both journals throughout thermajor part of thereciprocating movement of said stem, said one bearing which is locatednear said plug member having a portion of reduced diameter which engagesits cooperating journal in the final valve closing movement of Saidstem, whereby said journal and the cooperating bearing on said stem haveadditional clearance therebetween in the final axial travel ot' saidstem in a valve-closing direction.

2. In a high-temperature liquid-metal valve, a valve body having inletand outlet ports, an annular valve seat fixed in said body about one ofsaid ports, a movable plug member cooperating with said seat, anelongated valve stem on one end of which said plug member is carried,means for reciprocating said valve stem to move said plug member towardand away from said seat including two spaced bearings on said stem whichare reciprocable in journals, one of said journals being in the vicinityof said valve seat, said bearings and said journals having a closesliding lit during the major part of the axial travel of said stern,said bearing which is adjacent said movable plug valve having a portionof reduced diameter which is in engagement With the journal in saidvalve body during the last part of the axial movement of said stem inthe valve-closing direction, whereby the clearance between saidlast-mentioned bearing and its journal is increased and said plug memberis free to shift slightly laterally to locate itself in said annularvalve seat without galling said bearings.

References Cited in the le of this patent UNITED STATES PATENTS RaymondFeb. 15, Lane Mar. l5, Folmsbee Nov. 3, Charlton Aug. 5, Kmiecik Mar. 3,Connell Aug. 2, Thorp Apr. 3,

2. IN A HIGH-TEMPERATURE LIQUID-METAL VALVE, A VALVE BODY HAVING INLETAND OUTLET PORTS, AN ANNULAR VALVE SEAT FIXED IN SAID BODY ABOUT ONE OFSAID PORTS, A MOVABLE PLUG MEMBER COOPERATING WITH SAID SEAT, ANELONGATED VALVE STEM ON ONE END OF WHICH SAID PLUG MEMBER IS CARRIED,MEANS FOR RECIPROCATING SAID VALVE STEM TO MOVE SAID PLUG MEMBER TOWARDAND AWAY FROM SAID SEAT INCLUDING TWO SPACED BEARINGS ON SAID STEM WHICHARE RECIPROCABLE IN JOURNALS, ONE OF SAID JOURNALS BEING IN THE VICINITYOF SAID VALVE SEAT, SAID BEARINGS AND SAID JOURNALS HAVING A CLOSESLIDING FIT DURING THE MAJOR PART OF THE AXIAL TRAVEL OF SAID STEM, SAIDBEARING WHICH IS ADJACENT SAID MOVABLE PLUG VALVE HAVING A PORTION OFREDUCED DIAMETER WHICH IS IN ENGAGEMENT WITH THE JOURNAL IN SAID VALVEBODY DURING